EP = electrolytic polishing, which roughly reduces the variation of the peaks and valleys to 1/2 of the original surface. [next]
Characteristic and performance analysis of main parts of generator
Stator:
Stator consists of base, stator core and stator windings.
The base is welded by steel plate, the structure is light and sturdy, and the base is divided into many air inlet and outlet zones in the axial direction;
Stator coil:
It is stacked by strands of copper wire covered by polyester glass fiber, with half-unit type and basket shaped structure (parts of stator coils use transposition structure). The insulation grade of the stator coil is F grade. The stator coil is shaped by continuous wrapping and mould pressing with mica tapes. The coil end is firmly tied up to the support and the bundling ring with unidirectional tapes or dacron-glass ropes thus the turbo-generator unit became highly resistant towards sudden short-circuit conditions.
Stator core:
Stator core is punched and stacked by cold rolled non-oriented, high permeability, low loss high-quality silicon steel sheet, both sides of the silicon steel sheet are coated with a solid insulating film to prevent short-circuit between the stator core pieces to reduce eddy current loss.
Rotor:
The rotor is composed of shaft, coil, center ring, shroud ring and fan ring etc. The rotor coil is made of cold-drawn flat copper wires, and processed by oxygen-free annealing. The rotor coil of generator with 50MW and above is welded together by silver-bearing cold-drawn copper wires and adopts F grade insulation.
The shroud ring at rotor coil end is made of non-magnetic steel. Both ends of the rotor are equipped with centrifugal fan or axial flow fan with paddle fan blade which is forged by high-strength aluminum alloy.
Rotor machining:
The generator shaft is forged from an integral high-quality alloy steel and has an axial groove formed thereon for fitting a rotor coil and an air groove or a crescent groove is made in the large tooth to enhance the cooling of the main body and the coil end. The slots are processed by special machine for generator rotor processing, Tacchi high precision horizontal slotting and milling machine made in Italy, to ensure the high efficiency of generator.
The generator rotor must be subjected to high-speed dynamic balancing experiment and dynamic impedance experiment before delivery to verify the mechanical strength of the rotor and ensure excellent inter-turn insulation of the rotor windings.
(2)Model
Mainly produce the following model Steam Turbine Generator and the specifications are as follows:
Voltage(KV) Frequency(HZ) Power(MW)
2 poles Steam Turbine generator 6.3-3.8 50 3-60
6.6-13.8 60
4 poles steam turbine generator 0.4/0.69 6.3/6.6 10.5/11 50 0.5-30
0.4-11 60
QNP steam turbine generator uses closed-loop air self-circulation ventilation.
The rotors of turbo-generator under 50MW adopt indirect ventilation cooling method;
The rotors of 50MW and above turbo-generator is directly ventilated and cooled; an auxiliary groove is machined under the rotor winding trunking; air vents are machined on the rotor windings; with the action of the fan head and the centrifugal pressure head of the air vents, the rotor windings are directly cooled by air from the auxiliary groove and air vents.
(4)Excitation mode
QNP's steam turbine generator can adopt static silicon controlled type, two-pole AC brushless excitation and three-pole AC brushless excitation, three kinds of excitation mode.
(5)Insulation system
Adopt class F insulation materials and insulation structure, during the running time, assess the system according to class B insulation grade, meanwhile some margin has been kept.
(6)Design and acceptance criteria
Design, manufacture, inspection are carried out according to the relevant national standards, at the same time can meet the International Electrotechnical Commission IEC34-1 latest standards. According to customer`s requirements, QNP`s steam turbine generator can also be designed, manufactured and accepted according to ANSI, NEMA and other international standards.
(7)Technical Performance Analysis
1.Output margin
The series of steam turbine generator of QNP keeps 10% output margin.
2.Loss and efficiency
The steam turbine generator of QNP optimized the design and farthest minimized the additional loss and wind abrasion of generator under no-load and short-circuit condition, improved the efficiency of the generator, in general, QNP steam turbine generator`s efficiency is 0.2% higher than domestic similar models in this industry. It is higher than the national efficiency standard on the same capacity level. For example: QNP 15MW steam turbine generator`s efficiency value can reach 97.65%, and the national standard value is 97%.
3.Running reliability
QNP's steam turbine generator adopts advanced manufacturing technology, especially the rotor`s overspeed test uses high-speed dynamic balancer, rotor`s balance precision has been greatly improved, and the rotor`s vibration value is decreased. So that the steam turbine generator`s running availability factor has been improved, and the unit`s forced outage rate is decreased. At present, the availability factor of the steam turbine generator can reach about 99%, and the forced outage rate fell to 0.04% to 0.4%. Overhaul interval is up to 5 years. And the unit life can reach to 35 to 40 years.
Model meaning
QFWD-3-2A
QF Steam turbine generator
W W means brushless, without W means static silicon controlled
D D means double support, without B means single support
3 Rated power
2 2 means two poles and means the rated rotation speed is 3000 r/min
4 means four poles and means the rated rotation speed is 1500 r/min
A means the design serial number: A.B.C.D
Steam Turbine Generator,Biomass Generating,Biomass Generation,Biomass Power Generation Shandong Qingneng Power Co., Ltd. , https://www.steamturbine.be
   In the field of architectural applications, the surface finish of stainless steel is important for a number of reasons.
   A corrosive environment requires a smooth surface because the surface is smooth and not easily fouled. The deposition of dirt can rust or even cause corrosion of the stainless steel.
   In the spacious hall, stainless steel is the most commonly used material for elevator decorative panels. Although the surface fingerprint can be wiped off, but it affects the appearance, it is best to use a suitable surface to prevent fingerprints.
   Hygienic conditions are important in many industries, such as food processing, catering, brewing, and chemicals. In these applications, the surface must be easily cleaned daily, and chemical cleaners are often used.
   Stainless steel is the best material in this area. In public places, the surface of stainless steel is often ridiculed, but one of its important characteristics is that it can be washed away, which is a remarkable feature of stainless steel over aluminum . The surface of aluminum tends to leave traces and is often difficult to remove. When cleaning the stainless steel surface, it should be cleaned along the lines of stainless steel, because some surface processing lines are unidirectional.
   Stainless steel is best suited for hospitals or other areas where hygiene is critical, such as food processing, catering, brewing and chemicals, not only because it is easy to clean every day, but sometimes with chemical cleaners, and because it is not easy to breed bacteria. . Tests have shown that stainless steel has the same properties as glass and ceramics in this respect.
1 . Natural appearance of stainless steel
   Stainless steel gives a natural, sturdy and radiant feel, and its natural color gently reflects the color of the surrounding environment.
2 . Basic types of surface processing
   There are roughly five types of surface finishes that can be used for stainless steel, which can be combined to transform more end products.
   There are five types: rolling surface processing, mechanical surface processing, chemical surface processing, textured surface processing, and colored surface processing.
   There are also some special surface finishes, but regardless of which surface finish is specified, the following steps should be followed:
1 Together with the manufacturer to agree on the required surface processing, it is best to prepare a sample as a standard for future mass production.
2 When using in large area (such as composite board, it must be ensured that the same type of base coil or coil is used.
3 In many architectural applications, such as the interior of the elevator, although the fingerprint can be wiped off, it is not beautiful. If you choose a textured surface, it is not so obvious.
   Mirror stainless steel must not be used in these sensitive areas. [next]
4 When selecting the surface processing, the manufacturing process should be considered. For example, in order to remove the beads, it is necessary to repair the weld and restore the original surface processing.
   The tread plate is difficult or even impossible to meet this requirement.
5 For some surface processing, grinding or polishing lines are directional, known as one-way. If the texture is made to be vertical rather than horizontal, the dirt is less likely to adhere to it and is easy to clean.
6 No matter which kind of finishing is used, it is necessary to increase the process steps, so increase the cost, so choose the surface plus
Work hours should be cautious.
   Therefore, architects, designers, and manufacturers need to have an understanding of the surface finish of stainless steel. Through friendly cooperation and mutual communication with each other, we will surely achieve the desired results.
7 Based on our experience, we do not recommend the use of alumina as an abrasive unless careful during use. It is best to use a silicon carbide abrasive.
3 . Standard surface processing
   Many kinds of surface finish has been the use of numbers or other classification methods indicate that they have been incorporated into the relevant standards, such as: "British Standard BS1449" and "American Association of stainless steel producer Commission standards."
4 . Rolling surface processing
   There are three basic rolling surface finishes for sheet and strip, which are expressed by the production process of the sheet and the village.
No. 1 : Hot rolled, annealed, pickled, and descaled. The treated steel sheet surface is a dull surface and is somewhat rough.
No.2D: better than N0.1 surface processing is dim surface. After cold rolling, annealing, descaling, and finally light rolling with a matte roller.
No.2B : This is the most commonly used in architectural applications. Except for the last light cold rolling with a polishing roller after annealing and descaling, the other processes are the same as 2D , and the surface is slightly illuminated and can be polished.
No. 2B Bright Annealing: This is a reflective surface that is rolled by a polishing roll and subjected to a final annealing in a controlled atmosphere. Bright annealing still maintains its reflective surface and does not produce scale.
Since the oxidation reaction does not occur during the bright annealing process, it is not necessary to perform pickling and passivation treatment. [next]
5 . Polished surface processing
No. 3 : It is represented by 3A and 3B . "
3A : The surface is uniformly ground and the abrasive grain size is 80 to 100 .
3B : The surface is polished, and the surface has uniform straight lines. It is usually polished with a belt with a particle size of 180 to 200 on a 2A or 2B plate.
No.4 : Unidirectional surface processing, low reflectivity, this surface processing may be the most versatile in architectural applications. The process steps are first polished with a coarse abrasive and finally with an abrasive having a particle size of 180 .
No.6: No.4 is further improved, and in an oil medium with an abrasive and a polishing tampico brushing No. 4 surface. This surface finish is not available in " British Standard 1449" , but can be found in the US standard.
No.7 : Known as bright polishing, it polishes the surface that has been ground very fine but still has a wear scar.
   Typically 2A or 2B plates are used , with fiber or cloth polishing wheels and corresponding polishing pastes.
No.8 : Mirror-finished surface with high reflectivity, often referred to as mirror surface finish, because the image it reflects is sharp.
   The stainless steel is continuously polished with a fine abrasive and then polished with a very fine polishing paste.
   It should be noted in architectural applications that such surfaces can be left handprints if used in places where people are heavily mobile or where people often touch them.
   The fingerprint can of course be erased, but sometimes it affects the appearance.
The surface processing described in the " official " standards and in the literature is only a general introduction, and the sample can best represent the type of surface processing. Polishing or finishing metal surfaces of various manufacturers will provide the sample processing, the user should be discussed with them.
6. Surface roughness
   The classification of rolling surface processing and polishing surface processing is to illustrate the extent to which it can be achieved, and another effective representation is to measure surface roughness. The standard measurement method is called CLA (center line average), and the gauge moves laterally on the surface of the steel sheet to record the magnitude of the change in the peaks and valleys. CLA smaller number, the more smooth the surface. The final results for the different grades can be seen from the surface finish and CLA numbers in the table below.
7. Mechanical polishing Note:
We should remember that the grinding with sandpaper or abrasive belt in the grinding operation is basically a polishing cutting operation, leaving a very fine grain on the surface of the steel sheet.
We have had trouble with alumina as an abrasive, in part because of pressure problems.
Any abrasive parts of the equipment, such as abrasive belts and grinding wheels, must not be used for other non-stainless steel materials before use. Because it will contaminate the stainless steel surface.
In order to ensure the consistency of the surface processing, the new grinding wheel or belt should be tested on the same waste to compare with the sample.
8. Electropolishing This is a metal removal process in which stainless steel acts as an anode in the electrolyte and the metal is removed from the surface after energization.
This process is commonly used for the machining of parts because their shape is difficult to polish by conventional methods.
This process is commonly used on the surface of cold rolled steel sheets because its surface is smoother than the surface of hot rolled steel sheets.
However, electrolytic polishing makes the surface impurities more conspicuous, especially titanium and yttrium stabilized materials may cause differences in the weld zone due to particulate impurities.
Small soldering tips and sharp edges can be removed by this process. The process focuses on the protrusions on the surface and preferentially dissolves them.
The electropolishing process involves immersing stainless steel in a heated liquid. The ratio of liquids involves many proprietary technologies and patented technologies.
Austenitic stainless steel has a good electropolishing effect.
9. Reticulated surface finish Stainless steel can be used in a wide variety of patterns.
The advantages of having a steel plate with an added pattern or a textured surface are as follows:
1 Reduce the "oil can-ning", a term used to describe the surface of a bright material that is not optically angled. For example, a large-area decorative panel, even after stretch straightening or tension tensioning, is difficult to make the surface completely straight, and thus the metal roofing material shrinks. [next]
2 Reticulated pattern can reduce glare in the sun.
3 The tread plate is not obvious if it has slight scratches and small area indentation.
4 increase the strength of the steel plate.
5 provides the architect with a choice.
   Patented designs include fabric (for the Ed Mansion in London), mosaics, pearls and leather. Ripple and line patterns can also be used.
   The textured surface is particularly suitable for interior finishes such as elevator panels, counters, siding and entrances.
   For external applications, it should be considered that the stainless steel can be cleaned by rain and artificial washing to avoid dead spots that can accumulate dirt and airborne impurities, so as to avoid corrosion and affecting the appearance.
10 . Matte surface processing
   Mammal surface processing is one of the most common surface finishes. It is polished on a polished or brightly annealed steel surface with a nylon abrasive tape or brush.
11. Spray glass ball or shot peening
   For internal applications such as the interior of elevators, mixed surface processing is very popular.
   This mixing process consists of forming a ruthless surface by spraying a glass ball, then covering it with a masking process, coating the plastic film, and polishing the surface to form a polished and opaque mixed surface.
   Stainless steel sand pills can also be used in similar processes.
   The glass spheres or pellets to be used must not be used on other materials beforehand, especially on carbon steel. Because the carbon steel particles are embedded in the stainless steel surface, it is easy to cause corrosion.
   Ceramic balls can also be used as sprays.
12 . Color stainless steel
   The stainless steel color process was developed by International Nickel Corporation ( INCO ) in the 1970s , and many companies have licenses to use this process.
   As already explained, the reason why the stainless steel does not rust because Feeling chromium oxide film of its surface. [next]
   The color process uses this film to form a specified color.
   Since stainless steel utilizes this layer of film that is always present, it does not fade or maintain as often as paint.
   Color stainless steel can also be shaped to have no adverse effects on color even in sharp bends.
   Regarding the effect on corrosion resistance, tests have shown that the corrosion resistance is enhanced after using this process.
   This process is closely related to the operating time, and the color varies with time. The order of color changes is brown, gold, red, purple, and green.
   A major feature of the process is that its final appearance can reflect the original surface of the material, that is, the mirror or polished surface will produce a strong metallic luster, while the matte surface is processed without color.  Glossy.
   crafting process:
   The process is a stainless steel vessel immersed in a solution, the solution preferably containing 250 grams per liter of Cr2O3, containing 490 grams per liter of sulfuric acid may be a temperature range of 80 ~ 85 ℃, soaking time depends on the desired color, up to More than 25 minutes.
   After the steel sheet was rinsed with clean, cold water, at room temperature and then placed in a cathodic treatment at a concentration of 250 g / 1 liter hydrochloric acid and 2.5 g liquid / 1 liter of phosphoric acid, for about 10 minutes, a current density of 0. 2 ~ 0 . 4A/dm2 .
   In order to prevent damage, the color treatment is immediately followed by a hardening treatment, followed by rinsing in hot water and drying.
13 . Mixed surface processing
   The color stainless steel can be re-patterned, and the proprietary technology developed involves the removal of the " protruding " portion with a corundum belt , so that the end result is a combination of the natural beauty of the steel sheet and the color of the color pattern.
   This type of surface is not easy to leave a fingerprint, especially suitable for interior decoration.
Polishing manufacturers can provide surface processed samples.
14 . Etched surface processing
   The pattern is marked on the surface of the steel sheet by a laminating process, and the steel sheet is immersed in a ferric chloride solution ( grade o ), and the uncoated portion is etched away to form a beautiful pattern on the surface of the stainless steel.
The wide range of surface finishes in stainless steel broadens its field of application – different surface finishes make stainless steel surfaces different, making them unique in their applications.
Surface processing
CLA, micron
2B
0.1-0.5
2A
0.05-0.1
2D
0.4-1.0
3
0.4-1.5
4
0.2-1.5
8
0.2
EP
1/2 of the base value